FDA clears Regeneron's Arcalyst

The Food and Drug Administration has approved USA-based Regeneron Pharmaceutical's Arcalyst (rilonacept) for the long-term treatment of two cryopyrin-associated periodic syndromes disorders: familial cold auto-inflammatory syndrome and Muckle-Wells Syndrome.

Symptoms of both of these include inflammation such as joint pain, rash or skin lesions, fever and chills, eye redness or pain, and fatigue in both children and adults; however MWS is associated with more severe inflammation and may include hearing loss or deafness. In addition, some MWS patients may be affected by the build-up of a protein substance that damages organs and tissue. Both disorders affect about 300 people in the USA and are inherited.

Arcalyst blocks interleukin-1, which is a signaling protein secreted by certain immune-related cells in the body. Interleukin-1 acts as a messenger to regulate inflammatory responses, but in excess it can be harmful and has been shown to be key in the inflammation seen in CAPS sufferers with FCAS or MWS. The approval was based on positive questionnaire-based results in 47 patients who rated the drug's effect on five signs and symptoms of CAPS. Patients noted initial onset of relief of symptoms in their diaries within several days, noted the FDA.